Vehicle suspension

ABSTRACT

A suspension for a vehicle, which suspension includes a pendulum member upon which the wheel of the vehicle is mounted and which, in turn, is connected to a vertically oscillating suspension element on a pivot arranged transversely lower than the axis of the wheel. A stop is provided between the suspension element and the pendulum member to limit angular displacement of the pendulum member about its pivot, the stop being elastic in character and comprised of a material having elastic properties with the pivot of the suspension element being arranged on the inside of the bearing comprised by the elastic stop.

United States Patent [151 3,674,285

Grosseau 4s J l 4, 1972 s41 VEHICLE'SUSPENSION 3,174,771 3/1965 Muller..280/l24 [72] Inventor: Albert Grosseau, Chaville, France PrimaryExaminer A Ha"y Levy 731 Assignee: Citroen S.A. (Automobiles Citroen,Berliet, Attorney-$16k. fiipplewawbson Panhard), Paris, France 22 Filed:July 8, I969 ABSTRMT Appl. No.: 839,947

Foreign Application Priority Data July 9, 1969 France.. ..69l58551 US.Cl. ..280/124 R, 267/21, 280/962 Int. Cl ..B60g 3/ 14 Field of Search..280/l24, 124.3; 180/73 TL,

References Cited UNITED STATES PATENTS Muller ..280/1 24 X A suspensionfor a vehicle, which suspension includes a pendulum member upon whichthe wheel of the vehicle is mounted and which, in turn, is connected toa vertically oscillating suspension element on a pivot arrangedtransversely lower than the axis of the wheel. A stop is providedbetween the suspension element and the pendulum member to limit angulardisplacement of the pendulum member about its pivot,

the stop being elastic in character and comprised of a material havingelastic properties with the pivot of the suspension ele ment beingarranged on the inside of the bearing comprised by the elastic stop.

4 Claims, 9 Drawing Figures VEHICLE SUSPENSION BACKGROUND AND SUMMARY OFTHE INVENTION The present invention relates to vehicle suspensions ofthe type which comprise on each side of the vehicle a pendulum memberbearing the wheel and connected to a vertical oscillation suspensionelement by a pivot arranged transversely below the axis of the wheel andin which elastic stops are provided between the suspension element andthe pendulum member to limit the angular displacements of the latteraround its pivot. More particularly, since this would seem to be thearea of greatest interest, the invention concerns an improvementespecially to those suspensions in which the vertical oscillationsuspension element consists of a longitudinal arm articulated on thebody or frame of the vehicle by a second pivot parallel to that of thependulum member.

It is known that the longitudinal oscillations of the wheel thussuspended, which are due to the oscillations of the pendulum memberaround a transverse pivotal axis, to one side or the other of a stableposition of equilibrium wherein the axis of the wheel is vertical to thepivot of said member, have the effect of attenuating the rolling noisesand the impacts trans mitted to the body by the suspension members.

The object of the present invention is, in particular, to make this typeof suspension responds better than prior art constructions to thevarious requirements of actual practice, especially with regard to thecomfort and silence of a vehicle travelling on uneven ground.

For this purpose, the suspension defined above is characterized, inaccordance with the invention, by the fact that the pivot of thependulum member is arranged inside at least one bearing of anelastomeric or semi-elastic material, the elastic stops being adaptednot only to limit the angular displacements of the pendulum member, butalso to contribute to maintaining the pivot axis of the latter in asubstantially invariable position with respect to the suspensionelement.

BRIEF DESCRIPTION OF THE DRAWINGS In any event, the invention will bebetter understood from the following description, as well as from theaccompanying drawings, which description and drawings relate .to threepreferred embodiments.

F105. 1, 2, and 3 of these drawings show a suspension constructed inaccordance with a first embodiment and include a view in partialvertical section along line l--I of FIG. 2, a view in elevation and aview in horizontal section along the line llllll of FIG. 2,respectively;

FIGS. 4 and 5 illustrate schematically views in section along the linelV-IV of FIG. 3 and V-V of FIG. 1, respectively, showing two differentmanners of operation of the elastic stops;

FIGS. 6, 7, and 8 show a suspension which has been constructed inaccordance with a second embodiment of the invention and include a viewin vertical section along the line VI--Vl of FIG. 7, a view inelevation, and a plan view, respectivel F 1 G. 9 shows a thirdembodiment of the invention.

In the various Figures of the drawing similar numerals denotecorresponding elements.

DETAILED DESCRIPTION Before entering into the heart of the matter, itwill be useful to point out that, when an automobile moves over unevenground, the wheels undergo horizontal shocks which are not damped by thevertical suspension. These horizontal shocks are transmitted to theframe and to the body of the vehicle, and this results, in particular,in vibrations and driving noises which are unpleasant for thepassengers. It is known that, in order to decrease these driving noisesand increase the comfort of the vehicle, it is sufficient to permit aslight longitudinal oscillation of the wheel (that is to say, anoscillation parallel to the direction of travel), but that it isnecessary to limit to the greatest extent possible all the otherdisplacements which might aflect the road-keeping qualities of thisvehicle and, in particular, to modify the track-width, the toe-in (ortoe-out), and the camber of the vehicle. One thus provides the vehicle,so to say, with a horizontal" suspension which, by analogy with thevertical suspension, permits the wheels to oscillate longitudinally soas to absorb the horizontal impacts due to travel.

For this purpose, the suspension is provided on each side of the vehiclewith a pendulum member 5 or 5a which bears the wheel 4 and is connectedto a vertical oscillation suspension element by a pivot 7 or 7a arrangedtransversely lower than the axis of the wheel 4, and elastic stops areprovided between the suspension element and the pendulum member 5 or 50to limit the angular displacements of the latter around its pivot 7 or7a.

In accordance with the embodiments shown, the suspension elementconsists of a longitudinal arm l which is connected to the frame A by anelastic device 2 adapted, in turn, to transmit the suspended load andwhich can oscillate around a transverse shaft 3 rigidly connected to theframe. The wheel 4 is mounted on the member 5 or 54 via a spindle 6which is fastened either rigidly or for rotation (in the case of thedrive wheel), and can possibly pivot around a substantially verticalaxis (in the case of a steering wheel). The spindle 6 has its axislocated approximately in a horizontal plane parallel to the pivot 7. Thespindle 6 and the pivot 7 .are placed on opposite sides of the member 5.

In accordance with the invention, the pivot 7 or 7a is arranged insidean elastic bearing 8 (FIGS. 1-3) or of two bearings 8a (FIGS. 6-8) of anelastomeric or semi-elastic material, and elastic stops are arranged notonly to limit the angular displacements of the pendulum member 5 or 5a,but also to contribute to maintaining the pivot axis of the latter in asubstantially invariable position with respect to the arm 1.

In accordance with the embodiment of FIGS. 1-3, a flexible connection iseffected between the pivot 7, which is rigidly connected to the pendulummember 5, and the suspension arm 1. For this purpose, the pivot 7,consisting of a cylindrical part of revolution, is housed coaxially in arigid cylindrical sleeve 9 coaxial with the pivot 7 and rigidly fixed tothe suspension arm 1. In this case, the elastic bearing 8 isadvantageously formed of a rubber sleeve which is bonded to two metalsleeves (not shown), one outside the rubber sleeve and clamped in therigid sleeve 9 and the other inside the rubber sleeve and clamping thepivot 7. The bearing 8 is placed at the end of the rigid sleeve 9closest to the wheel 4.

The elastic stops are also formed of at least two cylindrical sleeves l0and 11 of elastomer. On the one hand, these sleeves l0 and 11 arearranged in cylindrical holes 12 and 13 drilled in the part of the pivot7 located on the inside of the rigid sleeve 9, but on the outside of thebearing 8; the axes of the holes which are staggered with respect toeach other are normal with respect to each other when there are two ofthem, one, for instance, being horizontal and the other vertical, andthey intersect the axis of the pivot 7 at the right angle. On the otherhand, these stops constitute a liner around cylindrical rods 14 and 15which are coaxial with the holes 12 and 13 and rigidly connected to therigid sleeve 9. Each of the stops 10 and 11 can advantageously beformed, as already described in the case of the bearing 8, of a rubbersleeve bonded to two metal sleeves (not shown), one of which, the outerone, is in contact with the pivot 7, while the other, the inner one, isin contact with the rod 14 or 15. Instead of arranging the elastic stopsbetween the pivot 7 and the rods 14 and 15, one could arrange thembetween the rods 14 and 15 and the rigid sleeve 9, the rods 14 and 15 inthis case being rigidly connected to the pivot 7 (and not the sleeve 9).The rigid sleeve 9 is advantageously given a length L at least equal tomm to allow a sufficiently long bearing 8 and be able to space the rods14 and 15 sufficiently away from said bearing. The center of the bearing8 can be considered to constitute an articulation point 0; the leverarms represented by the distances from the rods 14 and 15 to the point 0are then sufficient to prevent the pivot 7 from tilting around the point0.

In order to protect the parts arranged within the rigid sleeve 9, therecan be placed on the free end of the sleeve 9 farthest away from thewheel 4 a flexible plug 16, for instance of elastomer, which closes theannular space between the pivot 7 and the rigid sleeve 9 and preventsthe entrance of any external foreign body.

In accordance with the second embodiment shown in FIGS. 6-8, a flexibleconnection is provided, this time between pendulum member 5a and pivot7a, which is rigidly connected to suspension arm 1. FIGS. 6, 7, and 8relate more particularly to the suspension of a steering wheel 4controlled by a steering bar D, preferably parallel to the transversepivoting axis.

In this embodiment, the pendulum member consists of part 5a obtained byjoining together two non-secant U-shaped forks having the same centralplane and arranged in such a manner that the flanges of the Us aresubstantially normal to the sides of a right angle and that theconcavities of the Us are oriented towards the outside of the rightangle. The horizontal flanges Sab of the first fork are pierced in asubstantially vertical direction to receive a pin 17 around which thespindle 6 of the steering wheel 4 pivots. The vertical flanges Sac ofthe second fork are pierced in a substantially horizontal direction toreceive the pivot 7a around which the pendulum member 5a oscillates, thepivot 70 being rigidly connected to the suspension arm 1 whichterminates between the flanges Sac. Two elastic bearings 8a are arrangedin the holes pierced in the flanges Sac and assure a flexible connectionbetween the flanges Sac and the pivot 7a. These elastic bearings extendtowards the inside of the flanges Sac to constitute transverse stops 8abbetween the suspension arm 1 and the pendulum member 5a. Another stop,intended in particular to limit the longitudinal oscillations of thewheel, consists of an elastic cylindrical sleeve 10a with vertical axishoused in the pendulum member 5a and surrounding a vertical rod 14awhich is rigidly connected to the suspension arm 1.

As a result of these constructions, there is obtained an improvedautomobile suspension, the operation of which will first of all bedescribed with reference to the first embodiment of FIGS. 1-3.

As a result of the arrangement of the pivot 7 below the spindle 6, underthe effect of the weight of the vehicle and the reaction of the ground,the axes of the spindle 6 and the pivot 7 tend to move in one and thesame vertical plane. The equilibrium position is stable, and anydeviation from it gives rise to a return torque toward said position.

When the wheel 4 is subjected to a horizontal shock which acts parallelto the direction of displacement of the vehicle, this shock, transmittedto the spindle 6, produces a moment of rotation which tends to turn thepivot 7 around its axis, as indicated by the double-ended arrow a, FIG.2. The elastic bearing 8 opposes this moment of rotation with only asmall moment of resistance, but, on the other hand, the elastic stops 10and 11 oppose with a substantial moment of resistance due to theirmanner of operation indicated schematically by arrows in FIG. 5. As thepivot 7 turns through a small angle or around its axis with respect tothe rigid sleeve 9, the axis of the bore 12 drilled in the pivot 7 alsoturns through an angle a, FIG. 5, with respect to the axis of the rod 14which is rigidly connected to the sleeve 9. The result is a deformationof the sleeve 10 such that, on one and the same generatrix of thissleeve, one end 18 is compressed, while the other end 19 is tensioned.This manner of operation of the elastic sleeves is called conic working.The two elastic stops 10 and 11 which are thus deformed offer aprogressive moment of resistance which, while permitting a certainlongitudinal oscillation of the wheel 4, limits it to values which arerelatively low but which permit a dampening of the horizontal impacts.The spindle 6 describes, in fact, a small circular arc which may beassimilated to its tangent, parallel to the ground, and the oscillationcan be considered linear.

With regard to the oscillations of the wheel 4 as indicated by thedouble-ended arrow b, FIG. 3, and which correspond to variations intoe-in, it is seen that the bearing 8 and the elastic stop 10 operate incompression. This manner of operation is represented in FIG. 4 (wherethe direction of the forces is indicated schematically by an arrow), andit appears that all the points of one and the same generatrix are eithercompressed or tensioned. As the elastic or semi-elastic materials used,in particular, rubber, offer good resistance to compression, and as thedistance and, therefore, the lever arm between bearing 8 and stop 10 arelarge, the resistant torque produced by the stop 10 and the bearing 8,which are compressed, is substantial, and the oscillations in thedirection indicated by the double-ended arrow b, FIG. 3, are negligible.

Likewise, the oscillations in the direction of the doubleended arrow 0,FIG. 1 which correspond to variations in camber, are negligible, sincethe bearing 8 and the stop 11 work in compression and oppose a highresistance.

Finally, from consideration of the transverse displacements along thedouble'ended arrow d, FIG. 1, it is seen that the elastic stops 10 and11 both work in compression and, therefore, oppose a high resistance.The variations in tread resulting from such displacements can only benegligible.

The explanation of the operation of the embodiment of FIGS. 6, 7, and 8is similar to that given above.

The longitudinal oscillations of the wheel 4 in the direction of thedouble-ended arrow a, FIG. 7, are essentially limited by the elasticsleeve 10a which works in compression.

The oscillations of the wheel 4 along the double-ended arrows b and c,FIGS. 8 and 6, are made negligible by the resistance of the elasticbearings 8a which are spaced apart from each other and operated incompression.

The lateral displacements along the double-ended arrow d, FIG. 6, arealso negligible, since the elastic stops 8ab and 10a work incompression.

Thus, in this second embodiment, as in the first, only the longitudinaloscillations can assume a non-negligible amplitude which makes itpossible to absorb the horizontal impacts. One can, furthermore, formthe elastic sleeve 10a asymmetrically so as to impart it a slightflexibility in transverse direction to reduce the oscillations dcorresponding to variations in tread and a substantial flexibility inlongitudinal direction to permit limited longitudinal oscillations. Thisasymmetry is obtained, for instance, by pockets judiciously arrangedwithin the said sleeve. This remark also applies to the stops 10 and 11of the first embodiment. In both cases, the elastic sleeves 10, 11 ornot only limit the angular displacements of the pendulum member 5 or 5a,but also contribute to maintaining the pivot axis of the latter insubstantially invariable position with respect to the suspension arm.

Thus, both of the latter embodiments permit the wheel to oscillatelongitudinally without the toe-in, the track-width, and the camber beingsubstantially modified, thereby reducing the noise and the vibrationswithout changing the road-keeping qualities of the vehicle. Furthermore,as there is a break in continuity between the metal parts, an additionalfiltering of the residual vibrations is assured at the bearings andelastic stops, which increases the comfort of the vehicle. The life isincreased as a result of the absence of the rubbing of metal parts witheach other, and the manufacture is simpler which decreases the cost.

As goes without saying and as is, furthermore, evident from what hasbeen stated above, the invention is in no way limited to the specificapplications described or to the various specific parts which have beenshown and described; rather, the invention covers all variations,particularly those in which the hearing 8 and/or the stops 10 and 11 aremade of plastic or a semielastic material such as Vulkollan, or in whichthe bearing 8 is formed of a plastic ball joint as in the embodimentillistrated in FIG. 9.

What is claimed is:

1. In a vehicle suspension including a vertically oscillating suspensionelement having a transverse axis at one end,

a transverse pivot borne by the suspension element and coaxial with saidtransverse axis,

a pendulum member connected to said transverse pivot and bearing theaxle of a wheel of the vehicle, said pivot being arranged below saidaxle,

and elastic stop means arranged between said suspension element and saidpendulum member,

the improvement comprising at least one bearing of a material havingelastic properties within said suspension member and within which saidpivot is supported, and the elastic stop means comprising a rod elementand a rubber sleeve supporting and encircling said rod element, saidrubber sleeve being carried by said pivot, and said rod element beingradially positioned with respect to said pivot and rigidly fixed to saidsuspension element so as not only to limit the angular displacements ofthe pendulum member but also tending to maintain the axis of said pivotand said transverse axis coaxially aligned.

2. In a suspension according to claim 1, the further improvement of thepivot being rigidly connected directly to the pendulum member and saidelastic bearing being formed of a cylindrical sleeve of rubber bonded tothe pivot and to a rigid sleeve connected to the suspension element. t

3. In a suspension according to claim 2, the improvement wherein saidelastic stop means further comprises and additional elastic stop formeda rubber sleeve bonded in a hole formed in said pivot, and a rod elementrigidly connected with the suspension element and bonded axially withinsaid rubber sleeve, the axes of said rod elements disposed substantiallyat right angles to each other, and intersecting the axis of said pivotat a right angle.

4. In a suspension according to claim 1, the improvement of thevertically oscillating suspension element being formed of a longitudinalarm and a second pivot parallel to that of the pendulum memberarticulating said longitudinal arm on the frame of the vehicle.

1. In a vehicle suspension including a vertically oscillating suspensionelement having a transverse axis at one end, a transverse pivot borne bythe suspension element and coaxial with said transverse axis, a pendulummember connected to said transverse pivot and bearing the axle of awheel of the vehicle, said pivot being arranged below said axle, andelastic stop means arranged between said suspension element and saidpendulum member, the improvement comprising at least one bearing of amaterial having elastic properties within said suspension member andwithin which said pivot is supported, and the elastic stop meanscomprising a rod element and a rubber sleeve supporting and encirclingsaid rod element, said rubber sleeve being carried by said pivot, andsaid rod element being radially positioned with respect to said pivotand rigidly fixed to said suspension element so as not only to limit theangular displacements of the pendulum member but also tending tomaintain the axis of said pivot and said transverse axis coaxiallyaligned.
 2. In a suspension according to claim 1, the furtherimprovement of the pivot being rigidly connected directly to thependulum member and said elastic bearing being formed of a cylindricalsleeve of rubber bonded to the pivot and to a rigid sleeve connected tothe suspension element.
 3. In a suspension according to claim 2, theimprovement wherein said elastic stop means further comprises andadditional elastic stop formed a rubber sleeve bonded in a hole formedin said pivot, and a rod element rigidly connected with the suspensionelement and bonded axially within said rubber sleeve, the axes of saidrod elements disposed substantially at right angles to each other, andintersecting the axis of said pivot at a right angle.
 4. In a suspensionaccording to claim 1, the improvement of the vertically oscillatingsuspension element being formed of a longitudinal arm and a second pivotparallel to that of the pendulum member articulatinG said longitudinalarm on the frame of the vehicle.